GMC Safari

2000 GMC Safari Drive Train / Driveline   

Trans problem. Hard 1-2 shift when hot. After 45min-1hr. Fine cold. Had it in and they replaced the 1-2 valve and checked valve body. Said pan was normal. Still does it when hot. Been told by other trans guys: Needs solenoids relaced. Bad valve body. Bad converter. Never heard of this problem on a 4l60e. Circuit board. Needs total rebuild. Electrical problem. etc,etc,etc.

The solenoid would be the cheapest of all potential problems. You could possibly catch a bad solenoid by measuring ohms hot and cold.

Are you getting any check engine light or pending trouble codes (free code check at Autozone or Advance Auto)?

Thanks, I have no check engine light or ses light at anyrime. Not even with the key on posistion. The only code that ever comes up is 1870. Thanks

The check engine light is inoperative but you have recently had the codes checked?

Yes, they used a scanner from the underdash connetor.

You are taking too long to reply.

Your first mechanic was right . Replace the bad solenoid , Recently had the same problem come in my shop relpaced the solinoid problem was gone

Also while driving you may see the rpms jump and you may get a check engine light but not always will the light come on .

I would be feeling that one of the solenoid pistons is binding when the trans warms up.
Hard to check the valve body when the transmission cools off by the time they get the pan off. All it takes is one tech not torquing the valvebody bolts properly and you end up with a bit of distortion. As little as 1 or 2 thou is enough to cause distortion in the valve body. The tolerances in the 4l60e (and other 'electronic' type transmisions) are a lot closer than the trans in the past and it does not take much to be a problem. Douglas' advice re: testing the solenoid with an ohm meter ia a valid one. Sometimes it is poss. to check it by immersing it in a pan of heated ATF and testing it hot.

1998 GMC Safari Fuel System   

I have a 1988 GMC Safari Van. It has a real problem while traveling down the road. It wants to chug and sometimes backfire when i give it gas. It runs really good when not in drive, at a stop light I have to put it in nutreal to keep it running. It has 120,000 miles on it, and has gotten new plugs wires and cap and rotor, wires replaced.

Which year is your GMC van, 1988 or 1998?

Which engine do you have?

Does the check engine light come on while the engine is running?

It is 1988 year Safari Van and a 4.3l engine. I also had the timing checked.

Also the check engine light does not come on while driving.

I think you should check fuel pressure with a gauge at this point.

Did you use aftermarket plug wires? If you did check for stray spark in low light conditions. Use extreme caution around moving engine parts!

1994 GMC Safari All Part Groups Chugging When driving Always

I need assistance on troubleshooting my vehicle's problems. The parts I have replaced are new including fuel pump,fuel screen,fuel regulator,oxygen sensor,throttle pos. sensor,idle controller,distributor cap,rotor,wires,spark plugs,pcv valve,air filter,......
I also removed and cleaned the EGR,removed the catalytic convertor, and savaged a good onboard computer, though using my OLD PROM.

Vehicle symtoms are: running rich,poor gas mileage,stalling,chugging and hesitation when accelerating.

Please Help!!!!!!!!

Have you tried the MAP (manifold air press.) sensor? I usually recommend checking for codes before replacing parts randomly.
Bruce

1994 GMC Safari Electrical / Lighting Systems   

1994 GMC AWD Safari with Rear heat and A/C (all options). Engine nearly stalls intermittently when a load is put on the electrical system while engine is at idle speed. 99% of the time, the engine runs like new even with 125,000 miles, but occasionally while sitting at a stop light and turning on headlights, fogs, interior lights, or the heater blowers, the engine will nearly stall and a pulse will come through the audio system the second the electrical component is switched on. The A/C compressor does not trigger the same problem. Most of the time, the engine idle speeds is maintained no matter what accessories are operating. The battery load tests well (is two years old). The alternator is four years old and has kept the battery fully charged since its installation. HELP!! What is happening? I woud think this is an alternator problem but I don't understand what could be going on. During one near-stall an orange dash light flashed but did not remain on long enough to identify.

Thank you,
Joel

Hi Joel, This sounds to me like a bad ground. If the existing ground for the systems that have the adverse effect is a poor one it may be "maxed out" before many of the devices are turned on.

Hard to describe. What I believe is needed at this point is a ground distribution chart. That would map where to look for ground points. I'll look for a chart.

A good start might be to inspect where the battery cables attach at both ends of each cable. The cables may well be tight but how clean are the connections? Is corrosion spreading down through the cable strands inside the insulation?

How long has the trouble been going on?

Note: I am in Oklahoma and we may lose power from the winter ice storm and snow. It may effect response times.

Roger

Roger,
Thank you for the fast response. The electrical problem started yesterday. I am guessing it will get worse and dont want to be stuck on a snowy road. I have not yet checked the battery connections, but i figured they were fine because unlike what I said earlier, (under closer inspection of my memory after reading new material) not all electrical loads trigger the engine stall. The front and rear heat/AC blowers do not cause the effect. I found this post online that suggests the headlights and dome circuit are also wired with the fuel pump. It seems plausible that when I turn on the lights the fuel pump is losing power and causing the loss of idle speed because of a bad ground or a faulty +.

Here is the post from the net:
#30 of 39 95 safari no start problem by crzmn1 Dec 23, 2006 (3:14 pm)
Reply | E-mail Msg

i have a 95 safari that just quit. it will turn over but wont start. replaced the feul pump and steering column checked the fuses and pump relay. now for the funny part everything works execpt for the fuel pump head lights and interior lights. did a test on the wiring at the back of the fuse block and found that a fuseable link wire was testing as grounded. if i jump power to the fuel pump fuse it will start any ideas would be nice as it is my grandparents van and they are handicapped thanx
Replies to this message:

• electricdesign (Dec 24, 2006 6:58 am)
#31 of 39 Re: 95 safari no start problem [crzmn1] by electricdesign Dec 24, 2006 (6:58 am)
Reply | E-mail Msg
Replying to: crzmn1 (Dec 23, 2006 3:14 pm)

That fuseasble link is testing as grounded because it IS connected to GROUND THROUGH THE LOAD. The problem is you have lost your SOURCE of POWER to that FUSEABEL LINK. Go back to THAT point and toubleshoot from THAT point, UPSTREAM towards the BATTERY and you WILL find your problem. Being that all the lights are out and the fuel pump is out, the problem must be at a major connection towards the battery, and because this fuseable link carries so much load, it must be electrically near the battery, drawingwise. In other words, the fuseable link is usually connected very close to the battery, so you must be close to finding the problem.
Good Luck,
E.D. In Sunny and Warm Florida

Thanks,
Joel

The power distribution diagram shows a Rust Colored Fusible Link supplies power to the headlight switch, the fuel pump relay and several other systems as well.

May I send you a power distribution diagram? What is your email address please?

Roger

[redacted]

Thanks!

I'll get the email ready. Keep in mind this is a power distribution diagram, not a system skematic. I wanted you to see how the fusible link system is relative to lights and fuel pump.

Tell me what you think,

Roger

Thanks for the power diagrams. After your last email, I disconnected and then reconnected the battery and the three relay modules (one of which controls the fuel pump) attached to a bracket on the top right side of the engine compartment. The battery cables are in good shape, but the screw/bolt that connects the postive cable to the battery has a lot of lead in the threads, so much I am concerned it will strip out soon. The battery is still under warranty so I think I can get it replaced if this happens; do you know of any quick fixes? Maybe wedge some lead foil into the hole and screw the bolt back in? A disconnect and connect my battery more than most people (I hook it up to an equalizing charger twice per year) and may have over tightened it once. I don't think the main battery connectioin could have been the fault causing the problem because if the connection could not deliver enough power to run the headlights and blowers then it probably couldnt start the car...but i could be wrong here. However, if the connection was intermittently breaking then the symptoms might be explained.

No more problems after about one-hundred more miles in various conditions...but I wont be surprised to see it return... any advice for the screw battery terminal that's about to strip out?

Thanks for your help. I will be much better prepared to deal with this it becomes a problem again.

Joel

No tricks for the battery post if it strips out. Depending on the seller of the battery a stripped out post is not warranty, it's a workmanship issue.

There is an after market device sold that is a battery quick-disconnect you may want to consider installing. It can be found at auto parts chain stores and RV supply stores. You could also do a GOOGLE search to check it out.

What's next?

Roger

Roger,

That is all for now, unless you know some rare tricks to improving the fuel economy of these AWD vans.... I'm lucky to average 16 mpg in the winter, 17 summer for mixed driving, but I know this is normal. Also, I need to take the dash apart and fix a lose connection to the instrumental panel lights at some point, but I have the Chiltons digital manual to instruct me on that.

Thank you for your help,
Is there a way to request your assistance or re-open this dialog in the future? If you don't mind me asking, how do you get paid for this? If I send more money (greater than 7 bucks) do you receive a bigger cut?

Joel

When the customer closes the question it takes the site administrator to reopen it. He must agree with the customer that there is unfinished business on the same issue, that the technician should not have yet been paid.

When a closed question is reopened the technician's fee will be backed out of his pay until he or another tech's answer is accepted. An answer accepted by the customer pays the tech that submitted the accepted answer...even if more than one technician tried.

When the customer accepts the technician's answer All Parts splits the posted fee 50/50 with the tech. To request that a specific technician answer your question just say so when posting the question.

Roger

1992 GMC Safari All Part Groups   

Bad vibration coming from rear upon acceleration after complete stop.

Hello, Have you begun looking for the trouble?

Things to consider include inspecting:

1. Universal joints on the driveshaft.
2. Tires may have tread area seperation.
3. Mud/dirt accumulating on the wheels.
4. Driveshaft yoke splines binding on the transmission output shaft.

Please advise,

Roger

The brackets that hold the axle to the leaf springs had rusted through, evidently the first one broke as I was driving and the second one broke as it was being towed.

What may I do for you? Sounds like you have things figured out.

Roger

I think (hope) we have the problem figured out, now we just need to repair it, thanks for your input.

If we are finished here and you will allow me to be paid please click on OK to finish up.

I invite you to write to All-Parts.com, Administrator, www.All-Parts.com for a refund. It will take awhile. I have nothing to do with accounts actions.

Many thanks,

Roger